Source : Webster's Revised Unabridged Dictionary (1913)

Instantly \In"stant*ly\, adv.
   1. Without the least delay or interval; at once; immediately.
      --Macaulay.

   2. With urgency or importunity; earnestly; pressingly. ``They
      besought him instantly.'' --Luke vii. 4.

   Syn: Directly; immediately; at once. See {Directly}.

Source : WordNet®

instantly
     adv 1: without delay or hesitation; with no time intervening; "he
            answered immediately"; "found an answer straightaway";
            "an official accused of dishonesty should be suspended
            forthwith"; "Come here now!" [syn: {immediately}, {straightaway},
             {straight off}, {directly}, {now}, {right away}, {at
            once}, {forthwith}, {in real time}, {like a shot}]
     2: without any delay; "he was killed outright" [syn: {instantaneously},
         {outright}, {in a flash}]